Block, who was executive vice president of Oracle's North America sales and consulting, decided to quit the company to pursue other opportunities, Oracle said in a regulatory filing in June last year.

There was speculation that he had been axed because of critical remarks he made about his superior, co-president Mark Hurd, and other aspects of Oracle's business. The instant-message remarks emerged in court filings in a lawsuit between Hewlett-Packard and Oracle.

Block worked with Oracle for 26 years. In his last role in the company, he led an 11,000-person team and built "a multi-billion dollar sales business unit that achieved record revenue growth and margin expansion over the span of 10 years", according to a statement Thursday from Salesforce.com.

Salesforce.com said Tuesday it was acquiring marketing software company ExactTarget for $2.5 billion, with the aim of building an annual revenue stream of $1 billion from its marketing product line.